Team,
need your help asap please.
10/24 @ 6am 45° my lexus wouldn't start up. It cranked, started, shutoff all in 2 secs.... I first thought it was the key pad. Tried other one and it started. Changed both key pad batteries. Drove rest of week fine...
10/30 @ 7am same thing around 40° Called AAA. Before he got here, it started right up around 57° . They told me weak battery. So I replaced it.
11/5 @ 6am same thing around 40° crank start stop. wouldn't start just crank at 32°. Waited 1 min and started right up....

12/10 @ 5am 28° cranked. Started up , rev to 2krpm. Shutoff... I tried to start all it does is crank ,but won't turn over. Pedal real stiff too... wait few seconds pedal move but still no start up. Cranks fast not like dead battery. Has 700cca 850ca. Battery good. Keypad good. What could it be?
ideas: battery (replaced) ; colant temp sensor,

 

What type of car and year is it?

 

Sorry. 2010 lexus gs350Awd. 63k miles if that matters

 

By keypad do you mean the battery in your actual keyfob? Could be a place to start

 

Sounds to me like a bad fuel pressure sensor

 

Yea I have two keypad /key fob /remotes. Both have new batteries. Used car all week

 

What makes you say that ? would it be an issue just in cold. Over 50° I have no isses

 

From what you explained it seems like the cars not getting fuel. From what you explained to us it turns over normally just doesn't fire on and does not show codes. Many have experienced these issues of intermittent starting, they would either disconnect and reconnect the plug and the car would start.

The sensor is not expensive, just kind of tight to get to it.

 

Yea and right above coolant too

 

Why Couldnt it be bad fuel pump instead of a sensor?

 

I don'tthink it would be. It works fine in warm weather. Been driving fine all week. Today was first below 35° day

 

Update: took to dealer. They said it's code: B2784 Certification ECU. - Smart key system. Antenna Coil Open / Short. Its either the engine switch ($300) or Certification ECU ($1100) Plus $300 for diagnosis & labor.

 

Was there a check engine light when they retrieved the codes?

 

nope. He said it was a stored code

 

Thats a new one to me! Did he tell you when that code popped up? I do see on ebay they sell ignition switches so it maybe a possibility it goes bad

Try taking apart your remote fob and the electrical with electrical cleaner or alcohol